1. Field of the Invention
The present invention relates to a cutting apparatus. More particularly, the present invention relates to a rotary torsion cutting apparatus for cutting an article without deformation, deflection or burring of the article.
2. Description of the Prior Art
Most mechanics, professional installers and even “do it yourselfer's” have come across the need to cut metal stock or PVC pipe. For example, it is common when installing a typical suspended ceiling that the metal tracks supporting the ceiling tile must be cut. Even physicians employ cutting devices when sizing metal tubes, and the like, for implant into the human body. In these situations, there is a strong desire to find a tool which will handle the cutting in a simple, fast and economical manner.
In addition to seeking out a cutting device capable of providing a simple, fast and economical cut, many applications require that the cut end of the stock material be substantially undistorted, retaining the profile of the stock material prior to cutting. For example, a system such as that disclosed in U.S. Pat. No. 6,460,306, to Nelson, requires that the profile of the elongated connector be unchanged so that flooring planks will readily engage the connector at all points thereof (even along the cut edge). Burring or distortion of the cut edges of the connector is, therefore, considered to be entirely unacceptable.
Cutting devices are well known in the art and range in complexity from very simple to extremely elaborate. They are used in a variety of applications, including, but not limited to, the medical, construction, plumbing and electrical fields. Scissors are an example of a simple cutting device and are considered to include any cutting device wherein a pair of rods rotates around a fixed pivot point. The handles are positioned at one end of the rods, while the blades which accomplish the cutting are positioned at the other end of the rods. Generally, material is placed between the blades of the scissors, at least one of which has been sharpened to a cutting edge and is offset from the other. The blades are then closed together using the handles. The motion shears the material placed between the blades. As such, scissors and cutting devices similar thereto are commonly referred to as employing a “shearing” type mechanism.
It is well known in the art that shearing type devices, for example, scissors, are often constructed with slightly bowed cutting blades such that only a single contact point is maintained as the blades move relative to each other while cutting an object. The single contact point moves along the blades as the blades are brought together while cutting. In addition to assisting in the cutting action of shearing type devices, the use of bowed blades creates a gap between the blades. The gap extends from the pivot point of the device to the single contact point which moves along the blades during the cutting action. The provision of a gap limits friction between the blades and minimizes the force required to move the blades. If one were to construct a shearing type device without a gap, the force necessary to move the blades relative to each other would render the cutting device practically useless. A severe disadvantage of the gap is the burring which results on the cut edge, as well as possible sources of material that may foul the cutting device.
Further complicating the structure and operation of prior art cutting devices is the fact that a rotational bearing is generally required to perform a cut. The inclusion of a rotational bearing necessitates a housing feature. Examples of this type of cutting device are found in the disclosures of U.S. Pat. No. 5,261,303 to Strippgen, U.S. Pat. No. 4,958,434 to Marschner, U.S. Pat. No. 3,494,233 to Kojima and U.S. Pat. No. 2,638,985 to Ross.
As such, a need exists for a cutting apparatus capable of cutting without the creation of burrs, the problems associated with fouling and the need for a housing. The present invention provides such a cutting apparatus. Unlike prior art cutting devices, the present invention utilizes a rotary torsion mechanism to achieve the requisite mechanical force necessary to cut an article. Torsion cutting in accordance with the present invention requires substantially less force than is required by cutting implements employing a shearing mechanism. Further, and unlike the prior art cutting devices, the present cutting apparatus eliminates burring, prevents fouling, eliminates the need for a housing (consequently any bearing feature) and eliminates the need for any offset (in all cases except for cutting round material). In addition, the present cutting apparatus does not limit the range of rotational movement used in cutting and the present cutting apparatus is, therefore, well adapted for cutting a wide variety of materials regardless of the cutting characteristics (i.e., whether the cut material is soft (requiring greater rotational movement) or hard (requiring limited rotational movement)) of the material.